We provide ground motion prediction equations for computing medians and standard deviations of average horizontal component intensity measures (IMs) for shallow crustal earthquakes in active tecton...

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NGA-West2 Equations for Predicting PGA, PGV, and 5% Damped PSA for Shallow Crustal Earthquakes:

We used an expanded PEER NGA-West2 database to develop a new ground motion prediction equation (GMPE) for the average horizontal components of PGA, PGV, and 5% damped linear pseudo-absolute acceler...

NGA-West2 Ground Motion Model for the Average Horizontal Components of PGA, PGV, and 5% Damped Linear Acceleration Response Spectra

The NGA-West2 project database expands on its predecessor to include worldwide ground motion data recorded from shallow crustal earthquakes in active tectonic regimes post-2000 and a set of small-t...

NGA-West2 Database

Empirical ground motion models for the average horizontal component from shallow crustal earthquakes in active tectonic regions are derived using the PEER NGA-West2 database. The model is applicabl...

Summary of the ASK14 Ground Motion Relation for Active Crustal Regions

We present an update to our 2008 NGA model for predicting horizontal ground motion amplitudes caused by shallow crustal earthquakes occurring in active tectonic environments. The update is based on...

Update of the Chiou and Youngs NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra

The NGA-West2 project is a large multidisciplinary, multi-year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The resea...

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NGA-West2 Research Project:

To investigate the nature of earthquake‐magnitude distributions on faults, we compare the interevent variability of surface displacement at a point on a fault from a composite global data set of paleoseismic observations with the variability expected from two prevailing magnitude–frequency distributions: the truncated‐exponential model and the characteristic‐earthquake model. We use forward modeling to predict the coefficient of variation ( CV ) for the alternative earthquake distributions, incorporating factors that would effect observations of displacement at a site. The characteristic‐earthquake model (with a characteristic‐magnitude range of ±0.25) produces CV values consistent with the data ( CV ∼0.5) only if the variability for a given earthquake magnitude is small. This condition implies that rupture patterns on a fault are stable, in keeping with the concept behind the model. This constraint also bears upon fault‐rupture hazard analysis, which, for lack of point‐specific information, has used global scaling relations to infer variability in average displacement for a given‐size earthquake. Exponential distributions of earthquakes (from M  5 to the maximum magnitude) give rise to CV values that are significantly larger than the empirical constraint. A version of the model truncated at M  7, however, yields values consistent with a larger CV (∼0.6) determined for small‐displacement sites. Although this result allows for a difference in the magnitude distribution of smaller surface‐rupturing earthquakes, it may reflect, in part, less stability in the displacement profile of smaller ruptures and/or the tails of larger ruptures. Online Material: Global surface‐displacement data, and identified sources of uncertainty.

Variability of Displacement at a Point: Implications for Earthquake‐Size Distribution and Rupture Hazard on Faults

Previous studies have found a systematic difference between short-period ground motions from aftershocks and main shocks, but have not used a consistent methodology for classifying earthquakes in s...

Classification of Main Shocks and Aftershocks in the NGA-West2 Database

A modification to the Rhoades et al. (2008) procedure for evaluating inhibition of very strong ground motions in strong-motion models is developed that accounts for the correlation in the total residuals. The modified method treats the intraevent and interevent residuals separately. The alternative method is applied to the Abrahamson and Silva (2008) Next Generation Attenuation (NGA) ground-motion model and strong-motion data set. We find that there is no statistical basis to indicate that the Abrahamson and Silva (2008) NGA model overpredicts the occurrence of very large ground motions.

Kathryn Wooddell

Papers

NGA-West2 Research Project:

Variability of Displacement at a Point: Implications for Earthquake‐Size Distribution and Rupture Hazard on Faults

Classification of Main Shocks and Aftershocks in the NGA-West2 Database

Evaluation of Evidence for Inhibition of Very Strong Ground Motions in the Abrahamson and Silva Next Generation Attenuation Ground-Motion Model